· Introduction Phosphogypsum PG is a waste material generated during production of phosphoric acid H 3 PO 4 from phosphate rock rich in apatite [Ca 5 PO 4 3 OH] via reaction with sulfuric acid H 2 SO 4 Chemically PG consists primarily of calcium sulfate dihydrate CaSO 4 ·2H 2 O Table 1 Worldwide 100 280 Mt/year PG is produced 85% of
· Read Location and stability of europium in calcium sulfate and its relevance to rare earth recovery from phosphogypsum waste American Mineralogist on DeepDyve the largest online rental service for scholarly research with thousands
The aim of the study was to evaluate the possibility to obtain guided bone regeneration with two types of physical barriers calcium sulfate and PTFE nonporous barrier in surgical defects created in rat parietal bones In the right parietal bone the
Chemical agents SO42 and Ca2 in phosphogypsum could be recycled to make high purity calcium sulfate whisker A key step in this process is to decompose phosphogypsum using NaOH solution to obtain Na2SO4 solution and Ca OH 2 residue In this decomposition process thermodynamic analysis indicates that the majority of impurities reports to the residue phase
Although phosphogypsum is mainly calcium sulphate dihydrate it contains elevated levels of impurities which originate from the source phosphate rock used in the phosphoric acid production Among these impurities radionuclides from 238U and 232Th decay series are of most concern due to their radiotoxicity
This is to our knowledge the first report of bone regeneration with calcium sulfate evaluated under transmission electron microscopy Calcium sulfate has been used in several fields in implant dentistry treatment of dehiscences and fenestrations immediate postextraction implants sinus augmentation procedures the filling of cysts or defects left after removal of impacted wisdom teeth
· The purity of anhydrous calcium sulfate whisker which has beencalcined in250 300℃ is higher % the aspect ratio addition the explorative experiment on calcium sulfate whisker reinforcedcomposites is launched the results showed the anhydrous and calcium sulfatehemihydrate whisker modified enhance the group fill the PE resins the PE/CSWcomposite
To prevent formation of calcium sulfate scale on high temperature desalination heat exchangers the inverse solubility of calcium sulfate requires high sulfate removal To selectively remove sulfate from seawater a weak base anion exchange resin Relite MG 1/P was used In synthetic seawater the resin shows high sulfate selectivity
In this paper the factors related to the morphology of calcium sulfate whisker CSW are discussed Most attention was devoted to the influence of co‐crystallized phosphorus in phosphogypsum—existing in the form of CaHPO4 · 2H2O—on the crystal growth which was ignored in the preparation of CSW from phosphogypsum in previous research
Phosphogypsum PG an industrial by product from the manufacture of phosphoric acid can be processed into non fired ceramic tiles by an intermittent pressing hydration process In order to promote the practical application of the technology calcium sulfate whisker CSW was used as reinforcing agent to increase the mechanical strength of PG tiles in this research The bending strength of
The phosphate industry is commonly associated with a large amount of waste phosphogypsum in its solid form The vast majority of phosphogypsum is usually discharged into the environment without any treatment and reuse In this work we investigate the valorization of the Moroccan phosphogypsum for manufacturing valuable products such as Ca OH 2 CaCO3 and Na2SO4
· Abstract Using waster residue phosphogypsum as raw materials calcium sulfate whiskers were prepared by the hydrothermal method The products were characterized by XRD SEM and FT IR etc The effects of reaction temperature and time initial solid to liquid ratio of slurry and different additives on the morphology and content of the samples soluble
Calcium sulfate cement combined with silica based mesoporous material for bone regeneration in vitro and in vivo study Honglue Tan1 2 Shengbing Yang2 Weifeng Liu3 Pengyi Dai1 Tingting Tang2 Wuyin Li1 1Luoyang Orthopedics and Traumatology Institution Luoyang Orthopedic Traumatological Hospital Luoyang China 2Shanghai Key Laboratory of Orthopedic Implants Department of Orthopedic
· Read Location and stability of europium in calcium sulfate and its relevance to rare earth recovery from phosphogypsum waste American Mineralogist on DeepDyve the largest online rental service for scholarly research with thousands of academic publications available at your fingertips
calcium sulfate is called phosphogypsum As a general rule 4 to 5 Mg to tons of PG are produced for every ton of phosphoric acid produced 3 In the United States phosphogypsum is currently being produced at a rate of 54 million Mg 60 million tons per year
CalMatrixTM Calcium Sulfate Bone Graft Binder reported no inflammatory response or other adverse effects on bone healing associated with the use of CMC Both calcium sulfate and CMC have been shown to be biocompatible materials that are well tolerated in the oral environment for use in guided bone regeneration 8 Conclusion statement of
Phosphogypsum and process wastewater are two special wastes from phosphoric acid production using the wet process In this process beneficiated phosphate rock is dissolved in phosphoric acid sulfuric acid is added to this solution and chemically digests the calcium phosphate The product of this operation is a slurry that consists of the phosphoric acid solution and a suspended solid
· Our results show that the phosphate rock was mainly composed of fluorapatite calcite perovskite quartz magnetite pyrite and kaolinite whereas phosphogypsum only exhibited dihydrated calcium sulfate The activity concentration of U series radioisotopes in phosphate rock was around 1640 Bq/kg 226 Ra and 210 Pb tend to be distributed into phosphogypsum by up to 80% whereas the
· T his controlled split mouth preclinical study was designed to evaluate outcome following surgical implantation of an allogeneic freeze dried demineralized bone matrix calcium sulfate DBM CS composite with a CS barrier in 3 wall intrabony periodontal defects in 4 dogs Control conditions included surgical implantation of DBM or CS and gingival flap surgery GFS alone
The calcium sulfate hemihydrate HH whiskers were prepared by using phosphogypsum PG as raw materials in autoclave free hydrothermal system The influences of glycerol content reaction temperature and ratio of solid/solution on whiskers growth were detected The whiskers with smooth surface and high aspect ratio were obtained with 1 9 ratio of solid/solution in a 50 vol% glycerol
· Shen Y et al Engineering Scaffolds Integrated with Calcium Sulfate and Oyster Shell for Enhanced Bone Tissue Regeneration Acs Appl Mater Inter 6
· Bone defects are a challenge for the dental clinician As widely accepted in guided tissue regeneration physically halting soft connective tissue proliferation into bone allows for bone regeneration This concept is the osteopromotion principle The aim of this study was to assess the osteopromoting effect of calcium sulfate as a barrier
calcium sulfat which c
· The use of guided tissue regeneration GTR procedures for the treatment of gingival recession has shown encouraging results and is gaining clinical acceptance However maintenance of space under the membrane remains a problem for clinicians Hence this case study was an innovative attempt to evaluate the effect of adjunctive calcium sulfate placement along with collagen membrane
· Location and stability of europium in calcium sulfate and its relevance to rare earth recovery from phosphogypsum waste Radha Shivaramaiah Radha Shivaramaiah 1 Peter A Rock Thermochemistry Laboratory and NEAT ORU University of California Davis Davis California 95616 Search for other works by this author on GSW Google Scholar Wingyee Lee Wingyee Lee 1
Calcium sulfate Angiogenesis Bone regeneration Rita Strocchi MD is a professor of anatomy in the Dental School of the University of Chieti Italy Giovanna Orsini DDS Giovanna Iezzi DDS and Antonio Scarano DDS are research fellows in the Dental School at the University of Chieti Italy Corrado Rubini MD is a researcher in the
· The XRD patterns showed the increase in the intensities of monosulphate and different forms of calcium aluminate C{sub 4}AH{sub 13} and C{sub 4}AH{sub 19} with phosphogypsum content Ettringite is less stable than monosulphoaluminate so it transformed into monosulpho aluminate after 24 h which persisted up to 168 h The mechanism of the hydration process of C{sub 3}A phase
· Impurity is an important factor that determines the crystallization process of α calcium sulfate hemihydrate α CSH but the effects of phosphorus impurities in waste phosphogypsum PG >75% CaSO 4 ·2H 2 O on the α CSH prepared using the salt solution method are still not well known In this context the phase transformation of PG to α CSH was
· 1988 Effects of phosphogypsum or calcium sulfate on aluminon reactive aluminum in solutions at varying pH Communications in Soil Science
· The proposal of a method for converting the phosphogypsum PG waste remains the focus of many researchers since its quantity growing considerably is causing serious environmental problems In the present study PG was converted into lithium sulfate and calcium sulfate solids in a continuous process throug
Using waster residue phosphogypsum as raw materials calcium sulfate whiskers were prepared by the hydrothermal method The products were characterized by XRD SEM and FT IR etc The effects of reaction temperature and time initial solid to liquid ratio of slurry and different additives on the morphology and content of the samples soluble phosphates were studied
Guided Bone Regeneration GBR Using Nano Crystalline Calcium Sulfate Bone Graft in Extraction Socket A Case Report Ziv Mazor DDS1 Robert Horowitz DDS2 Ioanna Chesnoiu Matei DDS MS2 Sachin Mamidwar MBBS MS3 1Private Practice Ra anana Israel 2New York University School of Dentistry 3Orthogen LLC Introduction The use of bone graft to replace the lost bone in extraction
Recommendation for calcium sulfate hydrate usage levels up to not for fragrance manure and phosphogypsum PubMed Influence of calcium and silicon supplementation into Pleurotus ostreatus substrates on quality of fresh and canned mushrooms PubMed Efficacy of ε polylysine lauric arginate or acidic calcium sulfate applied sequentially for Salmonella reduction on membrane
· Desulfurization of calcium sulfate in a multiple zone reactor William Morton Swift Iowa State University Follow this and additional works at https ///rtd Part of theChemical Engineering Commons This Dissertation is brought to you for free and open access by the Iowa State University Capstones Theses and Dissertations at Iowa State University Digital Repository It has
Calcium sulfate A four year observation of its use as a resorbable barrier in guided tissue regeneration of periodontal defects Compend Contin Educ Dent 17 1996 pp 895 899 Medline
The production of ammonium sulfate fertilizer from phosphogypsum is studied The phosphogypsum is considered by product from extraction process of sulphoric acid The mereseberg process is used a waste of phosphogypsum with ammonium carbonate to produce ammonium sulfate as a main product and calcium carbonate as a byproduct It is a process could be used as a successful method in
Phosphogypsum is a solid waste mainly composed of calcium sulfate P 2 O 5 and HF which is the by product of phosphorus fertilizer or production is estimated to be around 100 280 megatonnes per year globally and the main producers are in the USA China and Africa [1 2] How to use this special acid waste is a big problem because the bulk
· Abstract Using waster residue phosphogypsum as raw materials calcium sulfate whiskers were prepared by the hydrothermal method The products were characterized by XRD SEM and FT IR etc The effects of reaction temperature and time initial solid to liquid ratio of slurry and different additives on the morphology and content of the samples soluble phosphates were studied
· Preparation of α calcium sulfate hemihydrates α HH from phosphogypsum PG under atmospheric pressure has been a promising way to utilize PG In this study the phase transition from PG the main composition is calcium sulfate dihydrate DH to α HH is investigated in NaCl solutions with different concentrations and reaction temperatures under
The anhydrous calcium sulfate AH whiskers were prepared in H 2 O H 2 SO 4 autoclave free hydrothermal system by using phosphogypsum PG as raw materials The influences of solid/solution ratio reaction time H 2 SO 4 concentration and maleic acid on crystal growth were The whiskers with smooth surface and high aspect ratio were obtained in a 20 mass% H 2 SO 4 solution
· these studies crystallization of calcium sulfate dihydrate from pure chemicals is reported For instance Kopyleva et al 28 tested addition of 1 2% aqueous surfactant solution to the slurry before filtration and found that the specific cake resistance was decreased by 35 40% and the filtration rate was increased by times as well as decreasing of washing time by factor of 1
· Phosphogypsum CaSO 4 2H 2 O a by product of phosphate rock processing contains high amounts of impurities such P 2 O 5 F radioactive elements organic substances secondary nanominerals and ultrafine particles UFP enriched in metals and metalloids In this study we examine phosphogypsum PG collected from abandoned fertilizer industry facility in south Brazil Santa